mong moi nguoi giup cho
Cho tam giac ABC. CMR neu tan
\fra
c{a}{2
}:tan
\frac{b
}{2
}:tan
\frac{c
}{2
} lap thanh 1 CSC thi cosA:cosB:cosC cung lap thanh mot CSC
mong moi nguoi giup cho
Cho tam giac ABC. CMR neu tan a
/2
:
tan b
\2
:
tan c
/2 lap thanh 1 CSC thi cosA:cosB:cosC cung lap thanh mot CSC